title: Differential detection of shrimp and crab for food labeling using polymerase chain reaction.
abstract: Shrimp and crab are well-known as allergenic ingredients. According to Japanese food allergy labeling regulations, shrimp species (including prawns, crayfishes, and lobsters) and crab species must be differentially declared when ≥10 ppm (total protein) of an allergenic ingredient is present. However, the commercial ELISA tests for the detection of crustacean proteins cannot differentiate between shrimp and crab. Therefore, two methods were developed to discriminate shrimp and crab: a shrimp-PCR method with postamplification digestion and a crab-PCR method that specifically amplifies a fragment of the 16S rRNA gene. The sensitivity and specificity of both PCR methods were verified by experiments using DNA extracted from 15 shrimp species, 13 crab species, krill, mysid, mantis shrimp, other food samples (cephalopod, shellfish, and fish), incurred foods, and commercial food products. Both PCR methods could detect 5 pg of DNA extracted from target species and 50 ng of genomic DNA extracted from incurred foods containing 10 ppm (μg/g) total protein of shrimp or crab. The two PCR methods were considered to be specific enough to separately detect species belonging to shrimp and crab. Although false-positive and false-negative results were obtained from some nontarget crustacean species, the proposed PCR methods, when used in conjunction with ELISA tests, would be a useful tool for confirmation of the validity of food allergy labeling and management of processed food safety for allergic patients.
authors.affiliation: Somatech Center, House Foods Corporation, Yotsukaido, Chiba, Japan. h-taguchi@housefoods.co.jp
authors.forename: Hiromu
authors.initials: H
authors.lastname: Taguchi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Watanabe
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Temmei
authors.forename: Takashi
authors.initials: T
authors.lastname: Hirao
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Akiyama
authors.forename: Shinobu
authors.initials: S
authors.lastname: Sakai
authors.forename: Reiko
authors.initials: R
authors.lastname: Adachi
authors.forename: Kozue
authors.initials: K
authors.lastname: Sakata
authors.forename: Atsuo
authors.initials: A
authors.lastname: Urisu
authors.forename: Reiko
authors.initials: R
authors.lastname: Teshima
mesh_terms: D000818:Animals; D001483:Base Sequence; D003445:Crustacea / Q000235:genetics*; D004247:DNA / Q000235:genetics; D017931:DNA Primers; D004797:Enzyme-Linked Immunosorbent Assay; D005515:Food Labeling; D016133:Polymerase Chain Reaction / Q000379:methods*; D013045:Species Specificity
chemical_list: D017931:DNA Primers; D004247:DNA